Punch strippers now in use are usually in the form of tubular members which are made of elastomeric material and sleeved on punches used to pierce holes in metal parts during stamping operations. The stripper strips the part from the punch when the punch is withdrawn. The stripper is held on the punch by friction alone.
One problem in the use of such strippers is that, through continued use, the frictional bond between the stripper and the piercing punch becomes weakened or loosened. When this happens the stripper can fall off the punch causing possible damage to the stamping equipment and almost certainly causing the loss of a number of pierced parts until the problem is detected and corrected.
In accordance with the present invention, the stripper is held on the punch by a magnetic holder. The magnetic holder may be in the form of a simple magnetic disc secured to the top of the stripper. The disc may have a flange or tabs embedded in the material of the stripper. The magnetic holder may also be in the form of a flux of solid grandular particles embedded in the end of the stripper.
One object of this invention is to provide a stripper with a magnetic holder which is of a simple, relatively inexpensive construction, is highly effective in retaining the stripper on the punch, and constitutes an improvement over strippers now in use including those shown in the following U.S. patents:
U.S. Pat. No. 115,157 Brown, et al
U.S. Pat. No. 2,805,717 Taylor
U.S. Pat. No. 3,234,835 Archbold, et al
U.S. Pat. No. 3,269,238 Whistler, et al
U.S. Pat. No. 3,485,122 Achler, et al
U.S. Pat. No. 3,690,205 Brown
U.S. Pat. No. 3,827,322 Saunders, et al
U.S. Pat. No. 3,871,254 Whistler, et al
U.S. Pat. No. 4,166,403 DiDonato, et al
U.S. Pat. No. 4,825,739 Pfaff
Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.